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BMSc > Personalised Medicine > Flashcards

Personalised Medicine Flashcards

1
Q

1a. Describe the epidemiology of oesophageal cancer (5 points)

A
  • half a million new cases/year
  • squamous cell carcinoma (SCC) is more common than adenocarcinoma (AC) globally, but AC predominates in Europe and North America
  • risk factors for SCC include smoking, alcohol, thermal injury, and micronutrient deficiency
  • risk factors for AC include acid reflux, Barrett’s oesophagus, and central (visceral) obesity. obesity, although a risk factor for reflux, is also an independent risk factor for oesophageal cancer due to the obesity metabolic syndrome
  • males are more commonly affected than females and most cases are diagnosed in 70-74 year olds
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2
Q

1b. Describe the histology of oesophageal cancer (4 points)

A
  • two types: squamous cell carcinoma (SCC) and adenocarcinoma (AC)
  • oesophagus is normally lined by squamous cells
  • SCC affects the upper and middle thirds of the oesophagus
  • AC affects the middle and lower thirds of the oesophagus; occurs due to acid reflux metaplasia
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3
Q

1c. Name the main symptoms of oesophageal cancer (5 points)

A
  • dyspepsia (reflux), particularly if new onset or worsening in a patient over 50
  • dysphagia
  • weight loss (malnutrition, cachexia)
  • symptomatic anaemia
  • haematemesis and melena
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4
Q

1d. Describe screening for oesophageal cancer (3 points)

A
  • conversion rate of Barrett’s to adenocarcinoma (AC) is low (0.3%), presenting a challenge to screening
  • 3-6% of patients over 50 with reflux have dysplasia or Barrett’s. Endoscopic radiofrequency ablation provides a very effective intervention, but endoscopy capacity is too low to undertake this screening
  • the solution is a cytosponge, a low cost device to detect Barret’s in GP. not yet at the stage of implementation, but it is close
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5
Q

1e. Describe the staging and management of oesophageal cancer (5 points)

A
  • treatment intent determined at an MDT meeting after staging investigations (CT TAP)
  • two additional investigations are undertaken if treatment intent is curative:
    – PET-CT (determines metastasis)
    – endoscopic ultrasound (tumour stage and node status)
  • curative treatments (30%): resection, oesophagectomy, lymphadenectomy, with/out chemotherapy
  • palliative treatments (40%): discussed in later cards
  • supportive treatments (30%): stenting (nutritional support), improving fragility, and symptomatic control (e.g., antiemetics for nausea)
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6
Q

1f. Describe the use of HER2 in oesophageal cancer treatment (3 points)

A
  • HER2 is present in 20% of adenocarcinomas (AC)
  • HER2 is detected by immunohistochemistry (IHC) generate a HER2 score (0-3+); a score of 0-1 will not benefit from HER2 therapy, a score of 3+ will benefit, and a score of 2 should undergo FISH
  • a high HER2 score will benefit from treatment of Herceptin (aka Trastuzumab)
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7
Q

1g. Describe the use of immunotherapy in oesophageal cancer (4 points)

A
  • the PD-L1 CPS biomarker predicts response to immunotherapy, particularly in adenocarcinoma (AC). a score of 5+ should be treated with immunotherapy
  • the PD-L1 CPS biomarker is positive in 50% of HER2-negative oesophageal cancers
  • where both HER2 and PD-L1 CPS are negative, high microsatellie instability (indicating deficient mismatch repair) may indicate benefit from immunotherapy
  • the SMC has approved Nivolumab as immunotherapy for oesophageal cancer
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8
Q

2a. Describe the risk factors and presentation of ovarian cancer (3 points)

A
  • risk factors: age (>50), nulliparity or low parity, delayed pregnancy, family history, BRCA1/2 mutation
  • presentation summary: BEAT (bloating, indicating ascites; eating less and feeling fuller; abdominal pain; and tell your GP
  • additional symptoms: pelvic mass, bladder dysfunction, pleural effusion, and shortness of breath
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9
Q

2b. Describe the treatment of ovarian cancer (3 points)

A
  • neo-adjuvant chemo +/- surgery (TAH, BSO, omentectomy, debulking) +/- adjuvant chemo
  • 60-70% respond to carboplatin or paclitaxel, although relapse rates are high
  • PARP inhibitors are used in maintenance treatments
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10
Q

2c. Describe the role of FGF signalling in ovarian cancer (4 points)

A
  • FGF expression confers resistance to platinum chemotherapy
  • FGF signalling influences homologous recombination (HR)-mediated DNA repair
  • ATM is one of the last components of HR-mediated repair; thus, knocking out ATM prevents DNA repair
  • siRNAs and ATM inhibitors can be used to re-sensitise cells to platinum chemotherapy
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11
Q

2d. Describe the role of the Multi-Drug Resistant 1 (MDR1) glycoprotein in ovarian cancer (4 points)

A
  • ovarian cancer cells upregulate expression of MDR1 and causes resistance of multiple chemotherapy drugs (e.g., paclitaxel and Olaparib, taxane and PARP inhibitor classes)
  • resistance occurs as MDR1 pumps drugs out of cancer cells (efflux)
  • verapamil can block the MDR1 pump and restore sensitivity to chemo drugs
  • careful choice of PARP inhibitor may limit the influence of the MDR1 response
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12
Q

2e. Where is current ovarian cancer research headed for future therapies? (3 points)

A
  • combining the common genes up- and down-regulated in ovarian cancer patients gives a ‘novel resistance signature’
  • once we know what these genes are, we can develop a test (ELISA, marker-based, or circulating tumour DNA), administered prior to chemotherapy
  • this test could determine which patients are resistant and therefore could avoid the toxicity associated with chemotherapy
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13
Q

3a. Describe the epidemiology and presentation of glioma (4 points)

A
  • 12,000 cases/year, 5,500 deaths/year, 12% 5 year survival
  • gliomas are asymptomatic until very advanced; ‘a mild headache is too late’
  • grade II and III gliomas are easily excised, but almost no gliomas are diagnosed at this stage
  • grade IV glioma, when most gliomas are diagnosed, cross the midline (‘butterflies’ or ‘gum on carpet’), meaning it is impossible to fully excise
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14
Q

3b. Describe the treatment options for glioma (6 points)

A
  • temozolomide (TMZ) is an alkylating agent used first line for glioma. 50% are resistant due to MGMT non-methylation
  • carmustine wafers: alkylating agent implanted in the brain after surgery. may cause infection and swelling
  • Avastin (aka bevacizumab) is an anti-VEGF monoclonal antibody. however, reduction of angiogenesis may prevent other therapies reaching the tumour
  • everolimus: an mTOR inhibitor only licensed in the USA due to stage 4 toxicity side effects
  • dabrafenib with trametinib: combination BRAF and MEK inhibitor; only useful in BRAF V600E mutations (a very small percentage of gliomas)
  • glioma is completely resistant to immunotherapy (i.e. a ‘cold’ tumour) due to high microglia count (these cells are anti-T cell)
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15
Q

3c. Describe the cells present in the brain (6 points)

A
  • microglia (immune cells, like macrophages, which arise from the yolk sac)
  • oligodendrocytes (maintain and generate the myelin sheath)
  • neurons (relay electrical signals)
  • astrocytes (form the blood brain barrier)
  • oligodendrocyte progenitor cells (OPCs; give rise to oligodendrocytes)
  • neural progenitor cells (NPCs; give rise to neurons, astrocytes, and OPCs)
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16
Q

3d. Describe the Verhaak classification of glioma (4 points)

A
  • Proneural: mutations in PDGFR(A), IDH1, TP53; closest to normal oligodendrocyte cells
  • Neural: association with oligodendrocyte and astrocyte differentiation, but mostly expresses neuron markers
  • Classical: mutations in eGFR, Notch, and Sonic Hedgehog, lack of TP53 mutations; best prognosis with aggressive treatment
  • Mesenchymal: mutations in NF1, TP53, PTEN; higher activity of astrocytic markers
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17
Q

3e. Describe the role of the nervous system in glioma development (1 point)

A
  • NPC-like, OPC-like, and neuron-like gliomas ‘feed off’ normal neuron signalling (neuroligin-3 secretion) to increase invasion and assume astrocytic/mesenchymal phenotypes
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18
Q

4a. Describe the epidemiology, risk factors, and screening of breast cancer (4 points)

A
  • Most common female cancer in UK, lifetime risk 1/8
  • Age is the main risk factor; 80% of cases occur in those over 50
  • Every female 50-70 will have a 3 yearly mammogram; after 70 it is the patient’s choice whether she wishes to continue with screening
  • Screening has increased survival from 40% to 70%
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19
Q

4b. Describe the triple assessment of breast cancer (3 points)

A
    1. Clinical history and examination (nipple changes, indrawing, lumps, skin/arm changes etc.)
    1. Radiology (mammogram if >40 or high clinical suspicion, ultrasound if discrete lesion)
    1. Pathology (core biopsy or large bore vacuum biopsy; gives a grade 1-3 and receptor status of cancer [ER, PR, HER2])
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20
Q

4c. Name the main genes associated with breast cancer

A
  • BRCA (1/2), PTEN, TP53, PALB2, ATM, CHEK2
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21
Q

4d. Describe the factors which make a BRCA-positive breast cancer more likely, and what preventative measures can be taken in these patients (4 points)

A
  • BRCA is associated with breast, ovarian, and prostate cancers
  • Factors [6]: family history of breast and/or ovarian cancer, young age at diagnosis, bilateral or multiple tumours, male breast cancer, co-existing prostate and pancreatic cancer, and triple-negative breast cancer (TNBC)
  • Surgical menopause recommended for BRCA-positive patients to reduce risk of cancer
  • Bilateral mastectomy improves survival in known gene mutations; the Manchester guidelines help guide which patients will benefit
22
Q

4e. Give an overview of breast cancer surgeries (3 points)

A
  • Two major types:
    o Breast conservation: lumpectomy, wide local excision, wire-guided local excision, magnetic seed tracing etc.
    o Mastectomy (traditional transverse, skin sparing + immediate reconstruction)
  • No significant difference in survival between the two, as long as conservative surgery has clear margins (<1mm), radiotherapy, 1cm excision at all margins, and full thickness at anterior and posterior margins
23
Q

4f. Other than surgery, name the treatment options for breast cancer (5 points)

A
  • Radiotherapy and chemotherapy
  • Endocrine therapies (e.g., tamoxifen, Herceptin)
  • Bisphosphonates
  • CDK4/6 inhibitors in ER+/HER2- (~70% of breast cancers)
  • PARP inhibitors (in BRCA mutations)
24
Q

4g. Describe the ‘reverse Walberg effect’ seen in some breast cancers (2 points)

A
  • Normal Walberg effect: cancer cells produce an abundance of lactic acid, which is used by epithelial cancer cells (carcinoma-associated fibroblasts/CAFs) to fuel oxidative phosphorylation
  • Reverse Walberg effect: CAFs undergo autophagy, producing ketones and fatty acids. These can be used by cancer cells for oxidative phosphorylation and are associated with a poor prognosis
25
Q

5A1 (ALL): Give the summary of acute lymphoblastic leukaemia (ALL) (5 points)

A

[remember ALL-STAR]
- 85% are B-cell ALLs, and 15% T-ALLs (thymic lymphoma)
- ALL is the most common cancer of children
- Associated with t(12;21) and a ‘starry sky’ appearance
- Symptoms are related to marrow suppression: symptomatic anaemia (e.g., fatigue), neutropenia (e.g., fever), and thrombocytopenia (e.g., bleeding)
- 95% of children achieve complete remission and 75-85% achieve cure

26
Q

5A2 (ALL): Describe risk stratification in ALL (4 points)

A
  • ALL patients are stratified with NCI risk criteria
  • Standard risk: age 2-10, low white cell count, and rapid response to therapy
  • Intermediate risk: age <2 or >10, high white cell count, and rapid response to therapy
  • High risk: cytogenetic risks (e.g., MLL gene) and slow response the therapy
27
Q

5A3 (ALL): Describe minimal residual disease (MRD) as it relates to ALL (4 points)

A
  • MRD describes the persistence of leukemic cells after chemotherapy at numbers below the sensitivity detection of normal cytomorphology
  • MRD reflects cellular resistance mechanisms, pharmacokinetic resistance, dosage and compliance, and other unknown factors
  • The MRD assay involves measuring the Ig heavy chain in B-cell ALL and T cell receptors (TCRs) in T-cell ALL
  • The 28-day MRD can therefore identify patients with disease-sensitive chemotherapy
28
Q

5B1 (HL): Give the summary of Hodgkin Lymphoma (HL) (5 points)

A
  • Average age of diagnosis 32 years
  • Characterised by Reed-Sternberg cells (‘owl’s eye’ appearance)
  • Associated with NF-kb and EBV infection
  • Presentation: painless lymphadenopathy (especially cervical nodes), fever, nephritic syndrome, obstructive jaundice, pain in lymph nodes on drinking alcohol
  • Staged by the Ann-Arbor system
29
Q

5B2 (HL): Describe the main chemotherapy regimen used to treat Hodgkin Lymphoma (HL) and its main risk (3 points)

A
  • ABVD: Adriamycin, bleomycin, vinblastine, dacarbazine
  • Main side effects are nausea and vomiting, myelosuppression, neuropathy and alopecia. Bleomycin is associated with pneumonitis and lung toxicity
  • ABVD significantly increases risk of secondary malignancy (especially female breast). Risk stratification by FDG-PET should be undertaken to reduce toxicity in those who do not need chemotherapy
30
Q

5B3 (HL): Describe the AVD (aka A+AVD) chemotherapy regimen used in Hodgkin Lymphoma (HL) (2 points)

A
  • AVD replaces bleomycin (associated with pulmonary toxicity) with Adcentris (aka brentuximab)
  • Adcentris (brentuximab) targets the CD30 receptor on lymphoma cells and enters the cell, where it releases MMAE (monomethyl auristatin E), inducing cell cycle arrest and apoptosis
31
Q

5C1 (CML): Describe the summary of chronic myeloid leukaemia (CML) (5 points)

A
  • CML is associated with the BCR-ABL translocation t(9;22) [mnemonic – Philadelphia CreaM cheese tastes best from 0900 to 2200]
  • BCR activates ABL, which induces RAS and JAK/STAT pathways
  • Myeloid cells are mature (blasts make up <10% circulating cells), helping differentiate from AML. Other blood findings include leucocytosis, increased platelets, hepatosplenomegaly, and lymphadenopathy
  • Natural history: chronic phase (most diagnosed here); 50% enter an accelerated phase (increasing anaemia and thrombocytopenia), which may terminate in the ‘blast crisis’ (CML converts to AML)
  • First line treatment is imatinib; second line (e.g., resistance to imatinib has developed) include other kinase inhibitors (e.g., dasatinib, nilotinib)
32
Q

5C2 (CML): When should imatinib (the first line defence against CML) be replaced with other tyrosine kinase inhibitors?

A
  • When resistance to imatinib develops; this means when BCR-ABL mRNA transcripts increase
33
Q

5C3 (CML): Describe the mechanism of action of asciminib, a second-line tyrosine kinase inhibitor used in CML (2 points)

A
  • Asciminib binds the myristoyl site of the BCR-ABL1 protein
  • The myristoyl site is inhibits BCR-ABL1; thus, by binding this site, asciminib mimics myristate and inhibits BCR-ABL1 activity
34
Q

5D1 (APL): Name the main clinical feature of acute promyelocytic leukaemia (2 points)

A
  • Blood coagulation abnormalities
  • Bleeding is exacerbated by conventional chemotherapy, thus risking early death
35
Q

5D2 (APL): Describe the mechanism of action of RAR-a (retinoic acid receptor alpha) and RXR (retinoid X receptor protein) in APL (3 points)

A
  • RAR-a is a nuclear hormone receptor which forms a heterodimer with RXR
  • The RAR-a-RXR heterodimer binds retinoic acid response elements (RAREs) to promote myeloid differentiation
  • The RAR-a-RXR heterodimer is formed by binding of retinoic acid, a vitamin A analogue
36
Q

5D3 (APL): Describe how the RAR-a-RXR heterodimer interacts with DNA methylation and acetylation to affect gene transcription (4 points)

A
  • Methylation of DNA suppresses gene activity
  • Acetylation of DNA increases gene activity. Histone deacetylases (HDACs) remove acetyl groups from DNA, meaning gene activity is decreased
  • In the absence of retinoic acid, the RAR-a-RXR heterodimer recruits enzymes such as HDACs, which silences (decreases) gene expression
  • When bound to retinoic acid, RAR-a-RXR undergoes a conformational change and releases the co-repressor, increasing gene transcription
37
Q

5D4 (APL): Describe how the PML-RAR-a protein causes malignancy (4 points)

A
  • PML-RAR-a cannot respond to physiological retinoic acid concentrations, meaning gene expression is decreased/repressed
  • PML-RAR-a binds a number of target DNA sites not recognised by normal RAR-a-RXR receptors, disrupting formation of PML nuclear bodies
  • It also recruits ‘repression’ machinery, including histone deacetylases (HDACs), histone methyltransferases, and DNA methyltransferases, further inhibiting expression of these genes and subsequent cell differentiation
  • The result is a block in differentiation at the promyelocytic stage, meaning these cells build up and cause malignancy
38
Q

5D5 (APL): Describe how APL is managed (4 points)

A
  • Exposing APL cells to all-trans retinoic acid (ATRA) or arsenic restores ability to cause cellular differentiation by releasing corepressors from the PML-RAR-a fusion protein, and also by degrading it
  • Pharmacological concentrations of ATRA also recruits histone demethylases, increasing gene transcription
  • Arsenic trioxide causes degradation of the PML-RAR-a protein
  • ATRA (or arsenic in resistant cases) greatly increases disease-free survival
39
Q

6a. Describe the epidemiology and name the three main types of skin cancer (4 points)

A
  • 1/3 of all cancers are those of the skin
  • in the UK, 1/5 will develop skin cancer; this is as high as 1/2 in Australia
  • incidence of skin cancer is greatly increasing (e.g., 5% per annum)
  • types: squamous cell carcinoma (SCC) and basal cell carcinoma (BCC) [keratinocyte cancers], and melanoma [melanocytes]
40
Q

6b. Describe the role of ultraviolet radiation (UVR) in skin cancer (3 points)

A
  • three main types of UVR: UVA (longest wave length, safest, ages skin and reaches the dermis), UVB (tans, causes redness/burns and skin cancer, reaches epidermis), and UVC (shortest wavelength, does not reach earth)
  • UVR induces formation of covalent linages producing CPDs and 6, 4 photoproducts; CPDs are 3x more frequent than 6, 4 photoproducts, but the latter are more mutagenic
  • UVR is a ‘complete’ carcinogen, causing DNA damage, p53/RAS signalling, inflammation, oxidative stress, etc.
41
Q

6c. Other than ultraviolet radiation (UVR), name the risk factors for skin cancer (4 points)

A
  • skin colour: darker tones are more protected than lighter tones due to presence of eumelanin rather than pheomelanin (latter of which absorbs UV light less efficiently, forms freckles and solar lentigines)
  • sun exposure: dose and pattern, sunburn in childhood, intermittent exposure (e.g., outdoor workers, elderly, sunbeds)
  • genetic conditions: xeroderma pigmentosum, oculocutaneous albinism, hereditary type VII collagen deficiency
  • immunosuppression: cancer, organ transplantation, immunosuppressive drugs (azathroprine, calcineurin inhibitors [ciclosporin, tacrolimus])
42
Q

6d. Describe the key points concerning basal cell carcinoma (BCC) (4 points)

A
  • occurs due to aberrant (constitutive) hedgehog signalling
  • patch (PTCH) inhibits smoothened (SMO), which causes downstream signalling and proliferation when active
  • 90% of BCCs occur due to inactivation of PTCH, and 10% due to activation of SMO
  • Hedgehog inhibitors (e.g., the SMO inhibitor vismodegib) are used ‘on and off’ in BCC, as the main side effect is causing food to taste disgusting (meaning many patients stop eating and become cachetic)
43
Q

6E1 (melanoma): name the main types of melanoma and their associated cell signalling pathways (2 points)

A
  • four types: BRAF-mutant (40-50%), NRAS-mutant (10%), NF1-mutant (10%), and triple wild-type
  • NRAS activates the BRAF-MEK1/2-ERK1/2 (MAPK signalling), and PI3K-AKT-mTOR signalling
44
Q

6E2 (melanoma): why is melanoma so resistant to conventional chemo- and radiotherapy? (2 points)

A
  • in normal cases, melanocytes need to be resistant to UV radiation to protect keratinocytes
  • melanomas, once metastasised, is therefore very resistant to chemo- and radiotherapy
45
Q

6E3 (melanoma): describe the use of vemurafenib/dabrafenib in melanoma therapy (3 points)

A
  • vemurafenib/dabrafenib used specifically in V600E mutations in BRAF
  • this blocks constitutive (‘always on’) BRAF-MEK-ERK signalling
  • BRAF inhibitors have spectacular short-term control but ultimately result in resistance due to additional BRAF mutation (e.g., BRAF becomes ARAF or CRAF)
46
Q

6E4 (melanoma): name the two main therapies used in unresectable melanoma [according to SIGN guidelines] (2 points)

A
  • BRAF + MEK inhibitor therapy (vemurafenib/dabrafenib + trametinib) used in BRAF V600E mutations, associated with toxicity
  • immunotherapy (immune checkpoint inhibitors) such as ipilimumab and/or nivolumab
47
Q

6f. Describe the key points regarding squamous cell carcinoma (SCC) (4 points)

A
  • SCC mutations include NOTCH1/2, TP53, FAT1, and FGFR3
  • NOTCH is a family of cell fate proteins (1-4) involved in signal transduction. in some tumours, NOTCH acts as an oncogene, but in others (including SCC) it acts as a tumour suppressor
  • cells with p53 mutations will not undergo apoptosis and are allowed to harbour many additional mutations
  • SCC has a recognised precursor, actinic keratosis (AK); 65% of SCCs arise from AK, but less than 1/1,000 AKs transform to SCC
48
Q

7a. Describe the epidemiology of colorectal cancer (3 points)

A
  • 2nd/3rd most common cancer after lung/breast, 40,000 cases/year
  • 5% are inherited and 25% are familial syndromes
  • risk factors: diet, red meat, dietary fat; factors that reduce risk include fruit and vegetables, folate, and NSAIDs
49
Q

7b. Describe hereditary non-polyposis colorectal cancer (HNPCC, aka Lynch syndrome) (4 points)

A
  • tends to present in younger patients and in the right proximal colon with one or a very small number of polyps
  • autosomal dominant, genes encoding DNA mismatch repair (MSH2, MLH1, MSH6, PMS2, EPCAM), causing microsatellite instability
  • additional cancer risks: endometrial, ovarian, other GI
  • Amsterdam criteria used to aid diagnosis (3+ family members with colon cancer, 2+ generations, 1+ case diagnosed before 50); patients at high risk have 2-yearly colonoscopies
50
Q

7c. Describe familial adenomatous polyposis (FAP) (5 points)

A
  • autosomal dominant, caused by mutation of the adenomatous polyposis coli (APC) gene. colorectal adenocarcinoma develops in 100%
  • patients develop hundreds of colorectal adenomas as teenagers, found through the entire colon and rectum
  • Gardner’s syndrome is a subset of FAP, characterised by skull and mandible osteomas, skin cysts, retinal pigmentation, fibromas, and sometimes desmoid tumours
  • APC pathway: Wnt stimulates Frizzled, which represses the APC complex. APC, when unrepressed, degrades beta-catenin by ubiquitylation. APC mutation prevents degradation of beta-catenin, which causes gene transcription
  • management is with prophylactic total colectomy
51
Q

7d. Describe screening for colorectal cancer (4 points)

A
  • FIT (faecal immunochemical test) is used yearly in adults 50-74 (Scotland; 60-74 in England)
  • FIT is a type of faecal occult blood test (FOB) which detects human haemoglobin in stool
  • those with an abnormal result are offered colonoscopy; 50% normal, 40% polyps (removed due to premalignant potential), and 10% cancer
  • one-off flexible sigmoidoscopy at 55 was trialed in England but abandoned due to lack of clinical endoscopists and COVID-19

BMSc (4 decks)

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